I know that this problem is well known and a simply google search give tons of results, but i think my probem is a bit different.

I'm on asus transformer prime ( TF201 )!
long story short: I extracted the lasted armv7a stage3 and lasted portage to a rw mountpoint and chroot inside.
all seems to work , gcc, bash, network, wget ....etc, but wget from emerge don't work.

the permission for /etc/resolv.conf is 644, and i yet tried:
FETCHCOMMAND="/usr/bin/wget -4 -O \${DISTDIR}/\${FILE} \${URI}"; # and
FEATURES="-userfetch"

PPS:
emerge --sync works fine. wget too.
this is really strange...
I write the IP for distfiles.gentoo.org in /etc/resolv.conf but it didn't work....that means that emerge-wget don't look in the /etc/resolv.conf?
# echo -e "140.211.166.134\tdistfiles.gentoo.org" >> /etc/resolv.conf

if you use dhcp i know dhcpcd per example and other dhcp server change the dns.
I would say : don't assume your resolv.conf file is fine, check it instead, as someone might change it for you without telling it.

and the file format is nameserver=dnsserverip (just because i see you've tried some weird echo -e "140.211.166.134\tdistfiles.gentoo.org" >> /etc/resolv.conf)
if you wish do that (resolving an url to an ip), the /etc/hosts file is there for that

If you were trying to tell wget to use ipv4 i would have tried something more looking like this, please note it's supposition this should works, i'm not really sure how the wget syntax should be, but should be close to this line

thanks for the suggestions, I've tried a lot of combinations of FETCHCOMMAND, but neither one solved the prolem.
but I've discovered a things that may be can help.
ping works fine only with root.
I checked the /etc/resolv.conf permissions and these is 644, but user 'max', with UID 1000 reiceve

I did it!
I was focus all my attention on the "unable to resolv" problem, without take care of my strange envinroment (android).
well, while i was developing my first socket program on android I saw that i can't create sockets.....a small google search and....
i found onethread which explain that android has special UID and GID for allow processes to certain resource ( such as create sockets ).
here are the resources: